The present invention relates to anti-contamination suits as used in industry where particulate contamination is of concern. Air particulates can include a number of components including: acids (such as nitrates and sulfates), organic chemicals, metals, and soil or dust particles. Of particular concern is radioactive particulates such as can be found in nuclear power facilities. Additionally, radioactive particulates would also be present in the event of a radioactive release such as through the detonation of a “dirty bomb.” In these areas it is desirable to minimize radioactive particulate exposure and associated radiation doses with respect to workers working in contaminated zones. To this end, workers or other remediation crews often utilize anti-contamination suits for protection. Anti-contamination suits and their associated breathing mechanisms are also sometimes referred to as respirators.
One problem frequently encountered in the art of anti-contamination suits occurs with respect to the suit and equipment post operation, that is, after the completion of the task which required the anti-contamination suit. After completing such a task, the suit and equipment which have been exposed to the contaminated environment must either be decontaminated or otherwise properly and safely disposed. Such decontamination or disposal can be quite costly and it is therefore desirable to limit anti-contamination suit parts which must be discharged in such a way.
Anti-contamination suits can be divided into two general types with respect to worker mobility namely, tethered and independent. Tethered anti-contamination suits are so named because the worker is necessarily connected to a separate or stationary air source via some air conduit connected to a breathing air compressor supply system or a bank of air bottles. Such suits have advantages only in the limited circumstances where the worker is restricted to a small radius from the air source. In such a circumstance, the worker is free from wearing additional devices which decontaminate the air. However, if the worker desires mobility, he is further restricted by the hose length and must be mindful of the air conduit as it has the tendency to crimp or otherwise restrict necessary flow.
The second variety of suits is generally described as independent. These anti-contamination suits are not tethered to a stationary air source and independently provide the worker with filtered air. These suits are desirable for their high degree of mobility. However, they are also plagued with a number of disadvantages. Independent anti-contamination suits do not require a breathing air source. Therefore, the user must wear air filtering equipment to minimize the intake of air borne particulates from the ambient air. As a result, bulky air blowers and battery packs of limited time duration add weight and awkward attachments to the suit. In many designs, blowers and filters are positioned around the waist of the worker and have conduit to deliver the air to the worker's head. Such suits suffer from low air flow to the face which results in a build up of excessive metabolic heat in the suit and fogging of the suit visor or hood. Excessive heat in the suit can lead to debilitating heat stress for the worker. Moreover, the addition of air conduit creates air flow resistance to push the air through the hose and, once again, adds the implication of potential crimping of any hose thereby restricting air flow.
Another problem prevalent to the independent air suit is the bulkiness of the added equipment. With respirators and blowers attached to the waist of the worker, the worker often has a difficult time accessing and maneuvering in tight settings. Often the work environment is very hot and the industry currently deals with the heat by having workers wear an optional “ice vest” which consists of a vest with big, heavy bags or compartments containing the common “blue gel” found in freezer packs. As this material goes from frozen to liquid form it often shifts downward in its location on the vest and can be perceived by the wearer as dead weight.
In nuclear industry facilities and other radioactive environments (such as would follow a nuclear mishap or “dirty bomb” detonation), the problems identified above with respect to tethered and independent anti-contamination suits are compounded by the intensity of the environment. In a radioactive environment, time is of the essence. Every second that a nuclear power operation is down while a worker is in the field addressing the problem costs vast sums of money. And, more importantly, every second that the worker is in a radioactive environment increases his exposure to radioactivity which increases the dose of radiation he receives. Therefore, it is of a great advantage when the worker is free and unencumbered so that he may perform his task and leave the radioactive environment in as little time as possible.
Unfortunately, under the current state of the art, anti-contamination suits having the above outlined drawbacks contribute greatly to the time spent in radioactive environments in order to complete a task. Awkward filter/blower placement on anti-contamination suits produce inefficient designs that fail to deliver good air flow to the user and limit mobility. These designs increase user discomfort and the time necessary to perform most tasks. Tethers or similar conduit in other suits are dependant on the hose length which limits mobility and requires the worker to spend time monitoring the line for crimps thus increasing the amount of time in the contaminated environment. Importantly, low volumes of air flow to the face and lack of air flow to the entire body contribute mightily to an overheating of the worker and a resultant inefficiency in work conditions. Furthermore, the short battery life of battery packs in the independent suits require the worker to spend even more time monitoring battery life and frequently changing or charging batteries. Taken together, these drawbacks found in the current state of the art lead to performance discomforts and difficulties while adding considerable time to accomplish a given task. Therefore, there is clearly a need in the art for a device which continues to shield the worker from harmful contamination yet also provides conditions which approach those that would exist if the worker wore no suit while completing a task at peek efficiency.